In the production of ornamental glass articles, it is common practice to cut sections of the pattern to be assembled from variously colored and variously textured glass sheets or panes and to assemble the sections in a predetermined orientation and pattern in the production of stained glass and leaded glass.
In particular, along the eges of each glass section, the copper foil is applied so that the edges of the foil overlap the faces of the article while the edge of the article is completely encased by the foil. The foil is available in rolls and has on its inner surface an adhesive coating of a pressure-sensitive adhesive which is covered by a masking or protective layer, e.g. of paper, which can be treated with a parting compound to facilitate the separation of the paper from the adhesive.
In the production of ornamental glass objects in the afore-described manner, the protective strip is removed from the adhesive backing of the foil and the foil is pressed as uniformly as possible against the edge so that the margins of the foil project outwardly. These overhanging margins are then pressed back onto the broad faces of the glass article.
When two such foil-edged glass sections are brought together and solder is applied with the aid of a soldering iron or a soldering gun, following the application of a flux, the solder is drawn into the interface between the foil covered edges by capillarity and the solder coats the margins of the foil strips applied to the edges of the two articles so that, upon hardening, the two articles are held in place in a channel formed from the solder and the copper edgings, thereby producing the "leaded" glass article.
As anyone who has ever applied such copper foil edgings to glass articles can testify, it is practically impossible by purely finger application techniques to avoid crimping and wrinkling of the copper foil and hence the formation of irregularities which can result in a lack of proper adherence of the foil to the glass, problems with respect to the close soldering of two foil-covered edges, and proper positioning of the various glass sections.
As far as I am aware, there has been no manually effective way to prevent these problems.